Physics:What's That About — Watch Your Step
On average， we take 8 to 10，000 steps a day. Over a lifetime， we'll cover a distance equal to walking around the world four times! So we'd better have a good pair of shoes to do it! Some of us strut in heels — or murder weapons; trudge in slippers — the most dangerous footware around; or plod in inconstruction boots — built to keep you from slipping. The boots and shoes were made for walking.
- Added：2006
- Country：America
- Duration：60
- Time of update：2011/8/16 11:07:05